Question

What are neutrinos and antineutrinos?

Answer 1

A neutrino is a fermion that interacts only via the weak subatomic force and gravity. The mass of the neutrino is much smaller than that of the other known elementary particles.

The antineutrino (or anti-neutrino) is a lepton, an antimatter particle, the counterpart to the neutrino. Actually, there are three distinct antineutrinos, called types, or flavors: electron antineutrino (symbol -ve), muon antineutrino (symbol -ve $\mu$), and tau antineutrino (symbol $v_T$).